Rock drilling machine



Dec. 22, 1931. BUNN ROCK DRILLING MACHINE Filed March 29, 1930 2 Sheets-Sheet Inventor Jar/7 e Jam/v A ttomey Dec. 22, 1931. BUNN 1,837,947

ROCK DRILLING MACHINE Filed March 29, 1930 2 SheetS-Sheef 2 In venior low/7e 34/7 A iiorney Patented Dec. 22, 1931 UITED LORNE BUNN, OETHE PAS, MANITOBA, CANADA nocx DRILLING MACHINE Application filed March 29, 1930. Serial No. 440,035.

This invention relates to new and useful improvements in rock drilling machines and has for its primary object to provide, in a manner as hereinafter set forth, a machine of this character embodying an internal combustion engine mechanism whereby the force of the exploding gases is utilized to actuate the drilling tool.

Another important object of the invention is to provide a rock drilling machine embodying means for forcing air under pressure through the drill in amannerto clear the hole which has been formed thereby.

Other objects of the invention are to provide, in a manner as hereinafter set forth, a

rock drilling machine of the character described which will be simple in construction, strong, durable, eflicient in its use and which may be manufactured at low cost.

All of the foregoing and still further objects and advantages of the invention may become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views, and wherein:

Figure 1 is a view in side elevation of the completely assembled machine.

Figure 2 is a view in longitudinal section thereof.

Figure 3 is a detail View in cross section showing the suction operated valve through which fuel passes into the machine.

Figure 4 is an enlarged sectional view of the air check valve which controls the entrance of air into the machine which is rejected through the fuel drill.

Figure 5 is a detail view in top plan showing a washer which is associated with the piston of the drill hammer.

Referring to the drawings in detail, the reference character 1 designates a vertically disposed cylinder having mounted on its up- "per end a crank case 2 in which is journaled for rotation a crank shaft 3 having a fly wheel 4 fixed o rifione end. A magneto 5 is mounted on the tubular support 6 which projects from the crank case and said magneto 5\ is operatively associated with the fly wheelin a manner to generate electric current. A piston 7 is coupled to the crank shaft 3 through the medium of the connecting rod 8. secured to the lower end of the cylinder 1 and in communication therewith is the hammer actuating piston cylinder 9 in which is mounted for reciprocatory movement the piston 10 mounted on the upper end of a rod 11 which extends slidably through a partition 12 into the hammer cylinder 13 in which is mounted for reciprocation the hammer 14 fixed on the lower end of the rod 11. The passage in the partition 12 through which the rod 11 reciprocates is provided with channels clearly indicated in Figure 2 of the drawings for the passage of air from the cylinder 9 tothe cylinder 13. A washer 15 having the notches 16 in its inner periphery is disposed on top of the partition 12 and a coiled spring 17 encircles the rod 11 and has 7 its opposite end impinged against the piston 10 and the washer 15. A cushioning washer 18 is disposed on the upper end of the hammer 14 for engagement with the partition 12 to cushion the return movement of said hammer 14 under the influence of the spring 17.

A drill 19 is mounted for reciprocatory movement in the lower end of a housing 20 which is slidably mounted over the hammer cylinder 13. The upper end of the drill 19 30 projects into the cylinder 13 for engagement by thehammer 14 for actuation thereby. The housing 20 is provided with an outt-urned flange 21 which is maintained yieldingly in abutting engagement with the flange 22 through the medium of the spring controlled rod 23. A substantially U-shaped stirrup 24 is provided with out-turned end portions 25 for abutting engagement with the flange 21 and the rod 23 projected transversely through the flange 21 and the end portions 25 of the stirrup 24 and are provided with heads 26. Coil springs 27 encircle the rod 23 and have one end impinged on the flange 22 and the opposite end impinged on the nut 28 threaded on the upper end of the rod 23. The closed portion of the stirrup 24 has a yoke shaped portion 29 therein in which-is disposed the drill 19 and said drill has formed thereon a stop flange 30 adapted to rest on the stirrup 24 to prevent the drill from falling out of the housing 20 and the cylinder 13 when the same is lifted from the ground.

A check valve 31 controls the passage of air into the cylinder 9 and said check valve is illustrated indetail inFigure 4 of the drawings.

A carburetor 32 is mounted on the cylinder 1 and communicates with the crank case 2 through the passage 33 and the port 34. An intake port 35 is provided for the cylinder and an exhaust port 36 is provided. A water circulating space 37 encircles the lower end portion of the cylinder 1 and the upper portion of the cylinder 9 and provided with intake and outlet passages 38 and 39, respectively. A spark plug 40 extends into the cylinder 1 for igniting the gases therein in t e usual manner.

The carburetor 32 has mounted therein a spring returned suction operated valve 41 and a stop screw 42 is provided to regulate .the movement of said valve. The carburetor 32 is connected to any suitable source of air supply. In use, on the down-stroke of the piston 7 the valve 41 is unseated and gas and air is drawn into the crank case 2 through the passage 33 and port 34. Upon'the upward movement of the piston, some of the gas is forced from the crank case 2 back into the chamber 33 and when the piston passes upwardly beyond the port 35 the gas enters the cylinder 1, it being understood that the valve 41 automatically closes. As the piston again moves down the charge is compressed and fired by the spark plug 40. The explosion of the charge drives the piston 10 and the hammer 14 downwardly under the tension of the coil spring 17 and said piston strikes the upper end of'the drill 19 in the usual manner. On the up-stroke of the piston 10, air is drawn into the cylinder 9 through the check valve 31, and on the down stroke of the piston the air is forced through the partition 12 and passage is provided therefor (not shown) in the piston 14 and thence through a central bore provided in the drill 19 and is discharged under pressure at the free end of said drill.

It is believed that the many advantages of v a rock drill machine constructed in accordance with this invention will be readily understood, and although the preferred embodiment of the invention is as illustrated and described, it is to be understood that changes in the details of construction will inders, a driven piston mounted for reciprocation in the other cylinder, the casin being further provided with a third cylinder in longitudinal alignment with said other cylinder, a partition disposedbetween the last named cylinders having an opemng therein provided with longitudinal channels in its periphery extendin between said last named cylinders, a rod xed to the driven piston and extending slidably through the opening into the third named cylinder, a hammer head fixed to the rod for reciprocation in the third named cylinder, a drill extending slidably into the third named cylinder for engagement and actuation by the hammer head, and a coil spring encircling the rod and having one end engaged with the partition and its other end engaged with the driven piston for yieldingly urging same toward the compressing piston.

Intestimony whereof I aflix my signature.

- LORNE BUNN.

be hadwhich will fall within the scope of the invention as claimed.

What is claimed is A rock drilling machine ofthe character described comprising a casing having longitudinally aligned, communicating cylinders therein, a charge com-pressing piston mounted for reciprocation in one of the cyl- 

